The biggest weakness the 49ers had was in their passing game. They averaged 183.1 yards per game passing, which was ranked 29th in a 32-team league. The 49ers wide receivers made only one reception for three yards in their defeat to the Giants.

Head coach Jim Harbaugh and GM Trent Baalke knew they had to upgrade the passing game. The 49ers signed free agents Mario Manningham and Randy Moss in an attempt to bolster their receiving corps. In addition, they selected wide receiver A.J. Jenkins with their first-round selection in the draft.

The 49ers focused on offense this offseason. They brought in a lot of speed and explosiveness on offense, while maintaining their stellar defense.

Quarterback Alex Smith had his best season as a pro. Under Harbaugh, Smith became a competent NFL quarterback. He completed 63.1 percent of his passes for 3,144 yards, both career highs. He also threw 17 touchdown passes against only five interceptions.

Harbaugh and the 49er faithful are expecting even more from Smith in 2012. The offensive weapons are much more potent and the 49ers should have a much improved passing attack.

Let's take a look at the 49ers' receiving corps and see who will be Smith's "go-to" receiver this year.

7. A.J. Jenkins

The San Francisco 49ers surprised most draft pundits by selecting wide receiver A.J. Jenkins with their top selection in the recent draft. Jenkins played his college football at the University of Illinois, where he led the Fighting Illini in receptions and yards.

Jenkins caught 90 passes in his senior season for 1,276 yards and eight touchdowns. These were particularly impressive numbers considering the fact that Illinois was one of the worst passing teams in college football.

Jenkins struggled with his conditioning, learning the playbook and catching the ball when the 49ers held their spring camp. He has looked a lot better in training camp now, but he is still a long way from being a top NFL receiver.

This season will be a learning experience for Jenkins. Although Jenkins could contribute as a return man, don't look for him to make much of an impact as a receiver.

6. Ted Ginn Jr.

Jed Jacobsohn/Getty ImagesTed Ginn is more valuable as a kickoff and punt returner

Ted Ginn Jr. returned to the 49ers this spring, as he found little interest for his services on the free-agent market. Ginn did a fine job returning kickoffs and punts for the 49ers, but he is not a reliable receiver.

Ginn had trouble catching the ball, as I recall numerous passes that bounced off his hands. Even when he did make the catch, it was rare if Ginn made clean receptions without juggling the football.

In 2011, Ginn had 19 receptions for 220 yards and no touchdowns. With the additions of Randy Moss and Mario Manningham, Ginn will be fortunate to have as many catches as he did last year.

4. Mario Manningham

Al Bello/Getty ImagesMario Manningham made a game-changing catch to help the Giants win the Super Bowl

The San Francisco 49ers must have used the theory, "If you can't beat em, buy em." The 49ers signed two New York Giants free agents this offseason. Brandon Jacobs will be used as a short-yardage back, and receiver Mario Manningham will bolster the 49ers' receiving corps.

Manningham was deemed expendable by the Giants, as Hakeem Nicks and Victor Cruz emerged as their top wide receivers. In 2011, Manningham had 39 receptions for 523 yards, well below what he produced in the prior two seasons.

Manningham will compete with Randy Moss for one of the starting wide receiver positions, but even if he doesn't win the starting job, he will get plenty of action. I fully expect Manningham to have a solid year, but he will not be Alex Smith's first receiver option.

3. Randy Moss

Randy Moss comes to the 49ers as a free agent after sitting out all of the 2011 season. He has looked very good in camp and should make a big impact on the 49ers' passing game.

Moss gives Alex Smith and the 49ers a legitimate deep threat, and his mere presence opens up the field for the rest of the receivers.

Head coach Jim Harbaugh has repeatedly stated how he has been impressed with Moss, both on and off the field. Moss has been a model citizen with the 49ers, thus far. He has taken the young receivers under his wing and helped them a great deal.

Moss has Hall of Fame credentials with 954 career receptions for 14,858 yards and 153 touchdowns. Although he will not be Smith's primary receiving option, Moss will get plenty of opportunities. As long as Moss keeps his focus and is a team player, he will be a huge asset for the Niners offense.

2. Michael Crabtree

Dilip Vishwanat/Getty ImagesMichael Crabtree led the 49ers in receptions in 2011

Michael Crabtree led the 49ers in receptions last year with 72 catches for 874 yards, both career highs. He also scored four touchdowns, a number which must increase in 2012.

Entering his fourth season with the 49ers, Crabtree is expected to lead the way as a starting wide receiver. Although I expect Crabtree to again lead the 49ers in receptions, I do not believe he will be quarterback Alex Smith's "go-to" guy.

The "go-to" receiver is the one player Smith can find whenever the 49ers need to make a play. It is the player who makes the key catch for the critical first down or touchdown. Although a decent wide receiver, Crabtree is not this "go-to" player.

Crabtree has trouble getting open against tight man-to-man or press coverage. The Giants showed that in the NFC title game when they played an aggressive, in-your-face style of defense against him. Crabtree was held to only one reception for three yards.

1. Vernon Davis

Doug Pensinger/Getty ImagesVernon Davis is an excellent blocker and receiver

Vernon Davis did not lead the 49ers in receptions last season, but he was quarterback Alex Smith's "go-to" guy. Whenever Smith and the 49ers needed a big play or a key first down, more often than not it was Davis who was the primary target.

In 2011, Davis caught 67 passes for 792 yards and six touchdowns. As a tight end, Davis gives a defense nightmares because he is too fast for most linebackers and too big for most safeties.

With the addition of Randy Moss, Mario Manningham and LaMichael James, who will get passes thrown his way out of the backfield, Davis' stats may not be improved from last year. Nevertheless, in crunch time, with the game on the line, Smith will look for Davis more often than not.

Smith has developed a very good chemistry with Davis, better than with any other 49ers receiver. When I think of a "go-to" receiver for Smith and the 49ers, it is Vernon Davis.

Although the 49ers will be hard-pressed to equal last year's 13-3 record, I still expect them to win their division and be a force in the playoffs.

The 49ers offense will be much improved over last season. Quarterback Alex Smith and the rest of the team will have a full training camp to learn and exploit the 49ers' complex playbook.

The 49ers have maintained their stellar defense from last year and brought in several more weapons for Smith to work with. This promises to be a fun and exciting season in San Francisco. Harbaugh has brought the winning attitude back to this storied franchise.